Hot Topic: The science of global warming and the public disconnect

The Intergovernmental Panel on Climate Change, created by the United Nations in 1988, recently released its fifth assessment report on global warming, finding a 95 percent scientific certainty that human activity such as the burning of fossil fuels causes climate change. But as the scientific consensus on climate change has increased, public opinion surrounding the issue has not followed.

A Rasmussen survey published Oct. 11 found that only 30 percent of likely voters in the United States consider global warming to be a “very serious” problem. And only 44 percent said global warming is primarily caused by human activity. Both those findings are in line with other national surveys this year. That disconnect is clearly related to several factors: the reality that some earlier forecasts have not come true; claims by some global warming adherents, such as former Vice President Al Gore, that were false; and a vocal campaign by some scientists and political groups to deny or at least raise skepticism about the dominant scientific consensus.

Scientists from San Diego’s Scripps Institution of Oceanography have been at the forefront of climate research since the 1950s. The U-T Editorial Board met recently with SIO scientists Jeff Severinghaus and Tim Barnett to discuss the IPCC report and the disconnect with public opinion. Below is an edited transcripts of both interviews.

Q: Could you summarize the findings in the latest IPCC report?

SEVERINGHAUS: They said five years ago that they were 90 percent sure that more than half the warming was human-caused in the past 50 years. Now they’re 95 percent sure. This is basic physics. There is natural climate change. We know that. And so if you’re going to make a statement like more than half of the warming over some particular time is due to humans, you also have to know how much was natural. And it’s just really hard to know how much is natural. And that’s why that figure is 95 percent and not 99 percent, or 99.99 percent.

Q: The main summary in the report is unequivocal. Since the 1950s many of the observed changes are unprecedented. The atmosphere and ocean have warmed. The amounts of snow and ice have diminished. Sea level has risen, and the concentration of greenhouse gases has increased. None of that, as you said, is really new — what’s new is the level of certainty?

BARNETT: They’ve also considered several other things. The global mean temperature people talk about, to me, is an idiot number. And it’s convenient. It’s easy. But that’s not where the action is, by any means. The action is in the ocean, which has been validated here. But I think in this one they brought in new players. The methane release from the permafrost is one. They’ve made a stab at some kind of model of Greenland and the glaciers. And the screaming message here — and we’re ocean guys — is they’re beginning to see impacts of this acidification on the plankton communities, which as you know is the basic building block of life in the ocean and, therefore, on the planet. The alarm bells in my head are certainly going off like crazy on these new things.

Q: The Economist, in a story in June, said some of the key predictions of 2007 on the rate of the heat increase just didn’t come true. Is the Economist wrong?

SEVERINGHAUS: There’s a scientific explanation of this. And that’s that the ocean basically takes up 95 percent of the heat that comes into the climate system. Think of heat as being in calories. And so the ocean in previous decades was taking up maybe 93 percent of the calories that were coming in. In the last 15 years it seems like what’s happened is the oceans have been taking up 97 percent of the calories. What has slowed down is the surface air temperature. But surface air temperature is just a tiny, tiny reservoir of those calories.

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BARNETT: The other thing you have to realize is that you’re thinking of climate as weather. Climate is really figured in decades. So what it does this year, maybe the earth’s temperature didn’t change for 10 years. That doesn’t bother me a bit, because we can look at everything else. The ocean’s a prime example. The deep ocean. And you can look at the Arctic. I mean, there are just list after list of things that are happening as they are supposed to happen.

Q: There’s a disconnect that shows up in the public opinion polls on the issue of global warming and what’s causing it and what to do about it. If the science is going in one direction and public opinion is going in the other, why?

SEVERINGHAUS: Disinformation. There’s millions and millions of dollars being spent to basically deceive people, frankly. It’s really, really alarming. And I wouldn’t say the science has settled, either. We’re not going to sit here smugly and say this is the final answer. It’s not. I’d like to raise an important misunderstanding that’s often out there. When people say they’re 95 percent sure that humans have caused the warming over the last 50 years, that’s kind of beside the point. The real point is that basic physics tells us that carbon dioxide traps heat. And we’ve known that since 1860. And we know it really, really well because to design heat-seeking missiles we had to deal with the fact that the CO2 coming out of enemy aircraft engines was actually confusing the heat-seeking missile because CO2 absorbs infrared radiation. So this is literally rocket science, if you want to think of it that way. And you add that with the fact that humans are going to be producing an enormous amount of CO2, maybe 10 times what we have produced already, and you realize the last 50 years is kind of beside the point. What we know for certain is that humans will change the climate dramatically in the next 100 years. Forget the last 50 years. What matters is the future.

BARNETT: And then you have some of these slimy characters like Heartland saying, “Hey, don’t worry. Even if you double CO2 it’s no big deal, you know.” Excuse me?

Q: But in the end it comes down to a political question: What do you do about it? And Congress, the world, frankly, is doing nothing. You must find that awfully frustrating.

BARNETT: Very frustrating.

Q: If CO2 stays in the atmosphere for 1,000 years, if we’re putting more and more into the atmosphere every day, does the question of what to do about it become one not so much of stopping CO2 but of adaptations here on Earth?

SEVERINGHAUS: Removing CO2 is going to become important. And there are technologies to do this. A professor at Columbia University, Klaus Lackner, has found a brilliant new method of removing CO2 using an ion-exchange resin. And it doesn’t actually require very much energy. the problem with so many of these old removal technologies is that they take energy to pull the CO2 out. And then that’s sort of a self-defeating cycle. But there’s new options. I believe in the power of technology to solve problems. And I think this ion exchange is great because it really just uses the evaporation of water in a desert environment as the source of energy. That’s free energy.

Q: How do you do that?

SEVERINGHAUS: The way it works is that you have, in a desert area, this ion exchange resin that is exposed to the dry air and then CO2 sticks to it. And then you pull it into a confined space and you flood that with water vapor. And the water vapor prefers the active site to CO2 so it kicks off the CO2. You collect your CO2 in your confined space and then you just put the plastic back out in the dry desert air and it repeats the cycle all over again.

Q: But how do you do that with the atmosphere?

SEVERINGHAUS: It’s amazing. Lackner’s done all the math on this. And he calculates if you could build 50 million of these little modular units, and they each remove one ton of CO2 a day, you could solve the problem. This is an exit strategy.

Q: If you could wave a wand tomorrow and achieve the political solution, what would that be?

SEVERINGHAUS: We need to figure out the details of the sequestration thing. There needs to be R&D. Right now it’s not commercially viable. Klaus Lackner and several other people I work with have been trying to start a private company for the past 10 years and it’s been a miserable failure. And the reason is it’s just not financially attractive right now. And part of the reason is that fossil fuels are just too cheap. It’s not quite ready for venture capital. But that’s the kind of thing we need. And the government, frankly, also has to put some money for R&D, as well.

BARNETT: The thing is, there’s a broad range of things that might be done. Maybe this is the right one, maybe it’s not. Maybe the next one will be the right one. But the point is we’ve got to do something.